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Over the past few years, virtualization has transformed the traditional data center. Countless businesses have reduced energy and hardware costs as more IT professionals realize the benefits of virtualization. For companies that demand more computing power, virtualization can help deliver improved performance without the need for an expanded facility or additional cooling infrastructure. Improved efficiency and reduced power use can easily be realized when multiple virtual machines (VMs) run on one server. Fewer physical servers and a smaller facility translate to lower overhead costs--put simply, virtualization allows businesses to do more with less.

Types of Virtualization: 

1.Application Virtualization.

2.Network Virtualization.

3.Desktop Virtualization.

4.Storage Virtualization.

5.Server Virtualization.

6.Data virtualization.

1. Application Virtualization: 

Application virtualization helps a user to have remote access of an application from a server. The server stores all personal information and other characteristics of the application but can still run on a local workstation through the internet. Example of this would be a user who needs to run two different versions of the same software. Technologies that use application virtualization are hosted applications and packaged applications. 

2. Network Virtualization: 

The ability to run multiple virtual networks with each has a separate control and data plan. It co-exists together on top of one physical network. It can be managed by individual parties that potentially confidential to each other. 
Network virtualization provides a facility to create and provision virtual networks—logical switches, routers, firewalls, load balancer, Virtual Private Network (VPN), and workload security within days or even in weeks. 

3. Desktop Virtualization: 

Desktop virtualization allows the users’ OS to be remotely stored on a server in the data centre. It allows the user to access their desktop virtually, from any location by a different machine. Users who want specific operating systems other than Windows Server will need to have a virtual desktop. Main benefits of desktop virtualization are user mobility, portability, easy management of software installation, updates, and patches. 

4. Storage Virtualization: 

Storage virtualization is an array of servers that are managed by a virtual storage system. The servers aren’t aware of exactly where their data is stored, and instead function more like worker bees in a hive. It makes managing storage from multiple sources to be managed and utilized as a single repository. storage virtualization software maintains smooth operations, consistent performance and a continuous suite of advanced functions despite changes, break down and differences in the underlying equipment. 

5. Server Virtualization: 

This is a kind of virtualization in which masking of server resources takes place. Here, the central-server(physical server) is divided into multiple different virtual servers by changing the identity number, processors. So, each system can operate its own operating systems in isolate manner. Where each sub-server knows the identity of the central server. It causes an increase in the performance and reduces the operating cost by the deployment of main server resources into a sub-server resource. It’s beneficial in virtual migration, reduce energy consumption, reduce infrastructural cost, etc.

6. Data virtualization: 

This is the kind of virtualization in which the data is collected from various sources and managed that at a single place without knowing more about the technical information like how data is collected, stored & formatted then arranged that data logically so that its virtual view can be accessed by its interested people and stakeholders, and users through the various cloud services remotely. Many big giant companies are providing their services like Oracle, IBM, At scale, Cdata, etc.

 It can be used to performing various kind of tasks such as:

• Data-integration
• Business-integration
• Service-oriented architecture data-services
• Searching organizational data 

Characteristics of Virtualization

Virtualization offers several features or characteristics as listed below: –

• Distribution of resources: Virtualization and Cloud Computing technology ensure end-users develop a unique computing environment. It is achieved through the creation of one host machine. Through this host machine, the end-user can restrict the number of active users. By doing so, it facilitates easy of control. They can also be used to bring down power consumption
• Accessibility of server resources: Virtualization delivers several unique features that ensure no need for physical servers. Such features ensure a boost to uptime, and there is less fault tolerance and availability of resources.
• Resource Isolation: Virtualization provides isolated virtual machines. Each virtual machine can have many guest users, and guest users could be either operating systems, devices, or applications.
• The virtual machine provides such guest users with an isolated virtual environment. This ensures that the sensitive information remains protected, and, at the same time, guest users remain inter-connected with one another.
• Security and authenticity: The virtualization systems ensure continuous uptime of systems, and it does automatic load balancing and ensures there is less disruption of services.
• Aggregation: Aggregation in Virtualization is achieved through cluster management software. This software ensures that the homogenous sets of computers or networks are connected and act as one unified resource.

Architecture of Virtualization

 In Cloud Computing, the end-users share the data on applications termed as the clouds. However, end users can share the entire IT infrastructure with Virtualization itself.

The virtual application services help in application management, and the virtual infrastructure services can help in infrastructure management.

Both services are embedded into a virtual data center or an operating system. The virtual services can be used in any platforms and programming environment. The services can be accessed through an on-premise cloud or an off-premise cloud.

Virtualization services are delivered to cloud users by third-party individuals. The cloud users, in return, have to pay third-party individuals with an applicable monthly or annual fee.This fee is paid to compensate the third parties to provide cloud services to end-users, and they also provide different versions of applications as requested by the end cloud users.

Virtualization is generally achieved through the hypervisor. A hypervisor enables the separation of operating systems with the underlying hardware. It enables the host machine to run many virtual machines simultaneously and share the same physical computer resources. There are two methods through which virtualization architecture is achieved described below:

• Type one: The first hypervisor type is termed a bare-metal hypervisor. They directly run over the top of the hardware of the host system. They deliver effective resource management and ensure the high availability of resources. It delivers direct access to the hardware system, ensuring better scalability, performance, and stability.
• Type two: The second hypervisor type is the hosted hypervisor. This is installed on the host operating system, and the virtual operating system runs directly above the hypervisor. It is the kind of system that eases and simplifies system configuration.

It additionally simplifies management tasks. The presence of the host operating system at times limits the performance of the virtualization-enabled system, and it even generates security flaws or risks.

Advantages of Virtualization

Here are some Pros/Benefits of Virtualization:

• Virtualization offers several benefits, such as it helps in cost reduction and boosting productivity towards the development process.
• It does away with the need to have a highly complex IT infrastructure.
• It facilitates remote access to resources and ensures that it promotes faster scalability.
• It is highly flexible, and it allows the users to execute multiple desktops operating systems on one standard machine.
• It removes the risks involved in terms of system failures, and it also boosts flexible data transfer between different virtual servers.
• The working process in Virtualization is highly streamlined and agile, which ensures that the users work and operate most economically.

Disadvantages of Virtualization

The disadvantages of Virtualization are very much limited in nature. Here are the cons/disadvantages of Virtualization:

• The transition of the existing hardware setup to a virtualized setup requires an extensive time investment, and hence this can be regarded as a time-intensive process.
• There is a lack of availability of skilled resources that helps in terms of transition of existing or actual setup to virtual setup.
• Since there is a limitation in terms of having less skilled resources, the implementation of Virtualization calls for high-cost implementations.
• If the transition process is not handled meticulously, it also poses a security risk to sensitive data.

Role of Virtualization in Cloud Computing

In Virtualization, a sensible or proper name is aligned with the physical server. The pointers are then directed towards that physical server, which is done on demand. Virtualization facilitates the execution of applications that are homogenous.

It also provides a virtual and isolated networking, storage, and memory area environment. The Virtualization is achieved through a host machine and guest machine. A host machine can be defined as the machine on which a virtual machine is developed, and the virtual machine so developed is termed as a guest machine.

Hardware virtualization plays a critical role by delivering infrastructure as a service solution most efficiently and effectively under a Cloud Computing process.

This type of Virtualization ensures portability. The guest machine is packaged as a virtual instance of an image, and such virtual images can be removed easily as and when the need arises.

Summary

• Virtualization helps create virtual versions of desktops, servers, operating systems, and applications.
• Virtualization comprises the host machine and virtual machine.
• Each virtualization system comprises of hypervisor, container, and virtual network.
• Virtualization offers scalability efficiency and helps in effective resource management.

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